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How evolutionary trees are used

Biologists use phylogenetic trees in many different ways to solve both scientific and practical problems. Using trees to make predictions about fossils Using trees to learn about the evolution of complex features Using trees to make predictions about poorly-studied species Using trees to learn about the order of evolution Using trees to learn about the evolution of diversity

Diversity of life organized into 3 Domains Bacteria- prokaryotic cells, unicellular and microscopic Archaea - like bacteria, prokaryotic cells, unicellular and microscopic Eukarya- eukaryotic cells, nucleus and organelles

The three domains are the three major “branches” of the “tree” of life

Domain Eukarya Domain Bacteria Domain Archaea Figure 1.5B The three domains of life.

Domain Bacteria Small prokaryotic cell organisms Can rapidly reproduce Most abundant organisms on earth Play critical roles throughout the biosphere Oldest known fossil One Kingdom Eubacteria

Domain Archaea Prokaryotic cell organism Unique biochemical genetic properties Some produce methane Believe to be earliest organism on Earth Inhabit some of the most extreme environments sulfurous hot springs, thermal vents, salty lakes, mining wastewater, intestines of some animals Divided One Kingdom Archaebacteria

Hot springs at Yellowstone National Park Domain Archaea Hot springs at Yellowstone National Park

Archaebacteria are grouped into three general categories Methanogens Obtain energy by using hydrogen gas to reduce carbon dioxide to methane gas Extremophiles Grow under extreme conditions Thermophiles (heat) Halophiles (salt) pH-tolerant Pressure-tolerant Nonextreme archaebacteria Grow in the same environments as bacteria do

Domain Eukarya Eukaryotic organisms, “true nucleus” Membrane bound organelles Complex cellular organization, biochemistry and molecular biology More diverse than any other domain of life

Eukarya is subdivided into four kingdoms Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia Kingdom

Protista Kingdom Protista are simple, predominately unicellular eukaryotic organisms. Examples includes slime, molds and algae.

Fungi Kingdom Fungi are unicellular or multicellular organisms with eukaryotic cell types. The cells have cell walls but are not organized into tissues. They do not carry out photosynthesis and obtain nutrients through absorption. Examples include sac fungi, club fungi, yeasts, and molds.

Plantae Kingdom Plants are multicellular organisms composed of eukaryotic cells. The cells are organized into tissues and have cell walls. They obtain nutrients by photosynthesis and absorption. Examples include mosses, ferns, conifers, and flowering plants.

Animalia Kingdom Animals are multicellular organisms composed of eukaryotic cells. The cells are organized into tissues and lack cell walls. They do not carry out photosynthesis and obtain nutrients primarily by ingestion. Examples include sponges, worms, insects, and vertebrates.

Conclusions from the Three Domain System All eukaryotes have true nuclei with linear chromosomes and membrane-bound organelles. The most variation in Eukarya is among protists. When considered from the perspective of the complete diversity of life on Earth, the fungi, plants, and animals are quite similar to each other.

Three Domains

TREE OF LIFE VIDEO http://tolweb.org/tree/home.pages/media.html Charles Darwin and the Tree of Life, narrated by David Attenborough 6:30sec

ANY QUESTIONS?

HOMEWORK QUIZ ??? Page 350 Answer questions 1-6